On Mon, 31 Oct 2005 08:43:14 +0000 (UTC), "David Cartwright"
wrote:

. The other thing to remember, of course, is that TIS relies on the
other aircraft giving a correct altitude - which in the aircraft I fly
relies on the the pilot having the correct altimiter setting.

I am fairly certain the TIS is using the encoder from the transponder
system to send altitude info. The setting in the Kollsman window has
no affect on the output.